diff --git a/public/js/appChart.js b/public/js/appChart.js
index 7ff9b4a6e0685f76adc76a62f8d9dc7d129680f8..322e88b47a9c634285ef7a1ceea3810c092347bc 100644
--- a/public/js/appChart.js
+++ b/public/js/appChart.js
@@ -7,7 +7,10 @@ import {
 
 import { calculateVorlaufMinusRuecklaufTemperature } from "./src_modules/calculateTemperatureDiff.mjs";
 
-import { getMetadataPlusObservationsFromSingleOrMultipleDatastreams } from "./src_modules/fetchData.mjs";
+import {
+  getMetadataPlusObservationsFromSingleOrMultipleDatastreams,
+  isFetchingRawMetadataPlusObservationsSuccessful,
+} from "./src_modules/fetchData.mjs";
 
 import {
   formatDatastreamMetadataForChart,
diff --git a/public/js/src_modules/calculateTemperatureDiff.mjs b/public/js/src_modules/calculateTemperatureDiff.mjs
index b63dc94260e557d4e45d93f5cb519127ef3f2a55..615c0238a117fca5463000d8cf3dfddacfa81cd4 100644
--- a/public/js/src_modules/calculateTemperatureDiff.mjs
+++ b/public/js/src_modules/calculateTemperatureDiff.mjs
@@ -175,16 +175,6 @@ export const calculateVorlaufMinusRuecklaufTemperature = async function (
           bldgDataPtSamplingRateNestedArr
         );
 
-      // If there is an error in fetching metadata + observations,
-      // the returned array will have this structure: [[undefined, undefined], undefined]
-      // Note that the second element is not an array as we would expect but is a
-      // a single `undefined` value
-      if (typeof observationsPlusMetadata[0][0] === "undefined") {
-        throw new Error(
-          `There was a problem in calculating the temperature difference (dT).\nThis is most likely due to a problem in fetching metadata and observations`
-        );
-      }
-
       // dT observations (timestamp + value)
       const vorlaufMinusRuecklaufTemperatureObs =
         calculateVorlaufMinusRuecklaufTemperatureObservations(
diff --git a/public/js/src_modules/fetchData.mjs b/public/js/src_modules/fetchData.mjs
index 2d6cbabab03a296b0d34fb96846f341511cd535f..7b2cca248743999b818759b29171433d99fe08f4 100644
--- a/public/js/src_modules/fetchData.mjs
+++ b/public/js/src_modules/fetchData.mjs
@@ -274,4 +274,31 @@ const getMetadataPlusObservationsFromSingleOrMultipleDatastreams =
     }
   };
 
-export { getMetadataPlusObservationsFromSingleOrMultipleDatastreams };
+/**
+ * Check whether the raw observations and metadata have been successfully fetched, otherwise throw an error
+ *
+ * @param {Array} observationsRawPlusMetadataArr A 1*2 array (the first element is an array that contans N Observations arrays; and the second element is an array of N Datastream metadata objects)
+ * @returns {Boolean} true, if the raw metadata and observations are successfully retrieved, otherwise an error is thrown
+ */
+const isFetchingRawMetadataPlusObservationsSuccessful = function (
+  observationsRawPlusMetadataArr
+) {
+  // If there is an error in fetching metadata + observations (raw observations)
+  // the returned array will have this structure: [[undefined, undefined], undefined]
+  // Note that the second element is not an array as we would expect but is a
+  // a single `undefined` value
+  if (typeof observationsRawPlusMetadataArr[0][0] === "undefined") {
+    throw new Error(
+      `There was a problem in fetching metadata and observations`
+    );
+  }
+  // If metadata + observations fetched successfully
+  else {
+    return true;
+  }
+};
+
+export {
+  getMetadataPlusObservationsFromSingleOrMultipleDatastreams,
+  isFetchingRawMetadataPlusObservationsSuccessful,
+};